Optimum Bracing Topology of Fixed-base Steel Frames

Steel structures bear lateral loads by moment frames, braced frames or dual systems. In braced frames slant compression-controlled members are designed to resist against lateral loads by axial forces tolerated through axial stresses. Structural design criteria of these members are based on current codes once the topology is selected by the designer. However, there could be quite a number of possibilities that may strike one s mind regarding the topology. In an optimal design, the material used to provide the required performance of the frame is of interest. To optimize the material, the overall weight of these structural members is addressed. In this research, a scheme is proposed through which the optimum topology of a bracing system may be determined before the structural design of elements profiles is performed. The bays of model frames to be braced are first filled with quadrilateral elements and then elimination is performed until an optimal design is delivered. Braces are then sized through code-based design procedures. The performance of the frame is evaluated in the last step to determine the topology efficiency.

Keywords:

topology optimization , braced steel frame , strain energy density , lateral load